1. Field of the Invention
The present invention relates to an internal combustion engine, and more particularly to a torque controller for internal combustion engines for preferably decreasing a torque fluctuation arising from combustion pressure variations and a cylinder block vibration induced by the torque fluctuation.
2. Description of the Prior Art
In internal combustion engines, it has been known that "gas torque" fluctuates according to the varying cylinder internal pressures due to suction and compression of intake mixture gas, expansion of combustion gas and the varying connecting rod angle with the crankshaft, and that "inertia torque" fluctuates according to the rotational inertia force variation. If such torque fluctuation is transferred to various components of accessory driven by the internal combustion engine, torsional vibration may arise in those components and deteriorate engine performance or damage the components; therefore, the torque fluctuation of the internal combustion engine must be reduced sufficiently. Then, a reaction of the torque fluctuation is transferred from a cylinder block to an engine support member, vibrates the member and noise increases, therefore such vibration must likewise be reduced.
To solve the problems, it has been proposed in, for example, Japanese Patent Laid-Open Number 185938/1983, to suppress a rotational torque fluctuation by generating a counter load torque on a crank shaft synchronously with the time when the rotational torque fluctuation generated by an internal combustion engine increases.
However, it is difficult to generate a counter load torque close synchronously with a torque fluctuation generated by the internal combustion engine. Namely, to cope with the requirement for detecting a torque fluctuation at high speed, it is necessary to calculate the value of the counter load torque necessary for canceling the torque fluctuation, and change the load torque by some available control means, and a series of processes detection, computation and control must be accelerated accordingly as an engine rotational speed increases; however this is rather unmanageable for the existing control techniques to implement.